One chance they get to learn? You can learn any time at any age... You should never stop learning and try to learning a little something every day or at least every week.
First you need to learn how to learn. You are doing a survivorship bias: you already know how to learn.
for example: if you had repetitive busywork for homework assignments, it doesnt make sense to spend a lot of time on it, once you have proven to yourself that you know how to do it anyway.